A traffic amount handled in cellular communication service such as third generation mobile phone service has rapidly increased under encouragement of introduction of a high speed packet communication protocol such as high speed packet access (HSPA), or the like. A user now can download large data such as music data and video streaming data from a network via cellular communication service. Long term evolution (LTE) which has been put into practical use in recent years is high speed cellular communication service also referred to as 3.9 generation mobile phone service. In the LTE, for example, by using orthogonal frequency division multiple access (OFDMA) in downlink, a peak data rate of 100 Mbps or higher can be realized. In the fourth generation mobile phone service which is to be put into practical use in around 2015, it is expected that a data rate of 1 Gbps at a maximum can be realized in a semi-fixed environment, and 100 Mbps at a maximum can be realized in a mobile environment.
However, such development of cellular communication service does not catch up with increase of data traffic, and there still remains a risk of local degradation of a data rate and occurrence of a network failure due to increase of system load. One measure against such a risk is introduction of a small cell. The small cell which is, for example, disposed so as to cover a hot spot where traffic is concentrated, can be used to complement radio communication service of a macro cell or provide specific service. A network formed by disposing a plurality of different types of cells such as macro cells and small cells in an overlapped manner is also referred to as a heterogeneous network. Patent Literature 1 discloses a technique of resting a small cell base station when there is no terminal in the vicinity and activating a resting small cell when there is a terminal in the vicinity for the purpose of saving power in the heterogeneous network.